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Determine which array elements are infinite



TF = isinf(A) returns a logical array containing 1 (true) where the elements of the array A are Inf or -Inf, and 0 (false) where they are not. If A contains complex numbers, isinf(A) contains 1 for elements with infinite real or imaginary part, and 0 for elements where both real and imaginary parts are finite or NaN.


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Create a row vector and determine the infinite elements.

A = 1./[-2 -1 0 1 2]
A = 1×5

   -0.5000   -1.0000       Inf    1.0000    0.5000

TF = isinf(A)
TF = 1x5 logical array

   0   0   1   0   0

Create an array of complex numbers. Determine whether the complex numbers contain infinite values.

A = [2 + 1i, 3 + 1i/0, 0/0 - 2i]
A = 1×3 complex

   2.0000 + 1.0000i   3.0000 +    Infi      NaN - 2.0000i

TF = isinf(A)
TF = 1x3 logical array

   0   1   0

The second element of A has an infinite imaginary part. For this element, isinf returns 1.

Input Arguments

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Input array, specified as a scalar, vector, matrix, or multidimensional array.


  • If x is a real scalar, exactly one of isfinite(x), isinf(x), and isnan(x) returns logical 1 (true).

  • For a complex scalar z, isinf(z) and isnan(z) can both return logical 1. For example, isinf(complex(Inf,NaN)) and isnan(complex(Inf,NaN)) both return logical 1.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

HDL Code Generation
Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.

Version History

Introduced before R2006a